Electric switch.



PATENTED OCT. 23, 1906.

' L. A. HAWKINS.

ELECTRIC SWITCH.

APPLICATION FILED PEB.1,1906.

Witnesses: 2f d524,.

Laurence/A. Hawkins,

JT't'bg I nnrrs era-"res ern-ar enrro LAURENCE A. HAWKlNS. orSCHENECTADY, newroarsv ASSIGNOR TO GENERAL 'ELECTRlG coMPANY, ACORPORATION or new roar.

sine-mic ewircn.

Specification of Letters ?atent.

Patented cat. as, 1906.

To all whom it may concern: Be it known that I, LAURENcE A. Haw- KINS,.a citizen of the United States, residing atlSchenectady, county ofSchenectady,

State of New York, have invented certain new and useful Improvements inElectric Switches, of which the following is a specification.

My invention relates to switches for electric circuits, and isparticularly applicable'to motor-starting switches, although it is notlimited to this particular application.

.For starting-largem ors it is frequently difficult and expensive toconstruct a single switch for successively cutting out the sec-. tionsof the starting resistance, since the amount of current in large motorsis great and trouble arises from arcing at the switchcontacts. It hasbeen proposed heretofore in such cases to employ a lurality ofswitchesof the ordinary knifeb ade type, each arranged to cut out a section ofthe resistance.

Separate switches ofthis type can easily be designed to handle thenecessary. current without arcing; but the sections of thestartingresistance cut out by the several switches ordinarily differgreatly in amount in order to obtain a smooth acceleration of the motor,

' and if the switches are closed in the wrong order excessive rushes ofcurrent may be produced" to the damage of the motor. It hasconsequentlybeen roposed heretofore to em loy a mechanica interlock forthe sevavoid the'necessity o ical interlock,.whi e a era switches-soarranged as to prevent their closing, except in a predetermined order.When all the switches are open, vall but the first switch aremechanically locked in open position. The closing of the first switchrenders it possible to close the second switch, and soon,"

The object of the resent invention is to emp oy'inga mechanfiordingproper protection to the motor against rushes of current due to closingthe wrong switch first. I secure this protection not by preventing theclosure of the switches except in a predetermined order, but insteadprovide means for .immediatel breaking the circuit if any switch is cosedout of its turn. plish this by means of a circuit-breaking de "vicecontrolled by auxiliary contacts con- 1 accomtrolled by the severalswitches. The.con,

Application filed February 1, 1906. Serial lilo. 2 99,021

acts are so arranged that if the switches are closed in the proper orderthecircuitbreak--- device reinams inoperative but if any. switch 1sclosed. out of its turn the circuit breaking device comes -i'nnnediatelyinto action to open the circuit. quate protection is obtained for themotor, 7 and the necessity of any mechanical connec ti'on' whateverbetween the several switches is avoided.

My invention in one aspect thus consists in the combination, with anelectric circuit, of a plurality of independentlymovable switches in thecircuit and means for automatically breaking the circuit upon closingthe switches out of a-predetermined order. v My invention furtherconsists in providing electrically-controlled means for reventing theclosing of the first switch un; ess all the. other switches are open. Ifit were not for this feature, the motor might be'jstarted up and thefirst switch opened so as to stop-the motor and then closed again withall there sistance' out of circuit. With my invention while it ispossible to' close any one of the switches first it is impossible toclose the motor-circuit except by opening all the switches and thenclosing the first switch, and it is im-' possible to keep the circuitclosed'except by closingthe remaining switches in the proper order. f

My' invention further consists in using a single magnet both to preventthe-closing of the first switch as long as anyone of the other switchesis closed and to trip the first switch upon the closing of any otherswitch out of its proper'order. w i My invention further c'onsists'inutilizing the 'no-voltage' release-ma "net ordinarily.

employed in motors for performing both of these functions. r

My invention further, comprises other fea- In this way adetures whichwill bepointed out specifically in the a' pended claims and will be bestunders'too b reference to ithefollowin'g specification an accompanyingdrawings, in which' Figure 1 shows diagrammatically an ar- ICO rangementof switches in accordance with my invention as applied to startinga'shuntture and F, the fieldpi a shunt-wound motor, and It represents asuitable resistance for connection in the motor-circuit at starting.

1, 2, 3, 4:, and represent five independently-movable switches. Switch 1is of the circuit-breaker typethat is, it is provided with a spring 6,which tends to pull it to open position when released by its latch.

L represents the latch for holding the switch in closed position, and Mrepresents the usual no-voltage release-magnet controlling the latch L.Whenever the magnet M is deenergized, the latch L is allowed to move soas to release the circuit-breaker 1..

This latch L is further arranged so that when the magnet M is denergizedand the switch 1 is'open the latch serves as a stop to prevent theclosing of the switch. In other words, magnet M must be energized inorder. that switch 1 may be closed, and if the magnet ecomes denergizedwhile the switch is closed the switch is immediately tripped. Theswitches 1 to 5 carry the auxiliary movable contacts 7, 11, 15,19, and23, respec tively, which in each position of each switch bridge a pairof stationary contacts in circuit with magnet M.

S represents a spring-actuated switch which is shown as of thepush-button type, normally open, but arranged when closed to bridgecontacts 27 and 28. B B represent leads from the bus-bars or othersource of current.

The switches are shown in the starting position. It will be seen thatthe circuit of magnet M is broken at switch S. This mag net isconsequently deenergized and the latch L is in position to preventclosing of switch 1. If switch S is depressed and if all the switchesare in open position, as shown, the circuit of magnet M will be closed,as follows: from lead B, through magnet M, contacts9,7,8,12,11,13a16,15,17,20,19,21, 24, 23, 25, and switch S, to lead B.The magnet M is consequently energized, shifting the pivoted latch L soas to permit the closing of switch 1. If, however, any of the switchesis closed, magnet M cannot be energized and switch 1 cannot be closed.For instance, if switch 2 is closed the circuit of magnet M will be openat contact 12. If switch 3 should be closed, the circuit of magnet Mwould be open at contact 16, &c. In other words, in order to closeswitch 1 all the other switches must be open and switch S helddepressed. It will be seen that when switch 1 is open the motor-circuitis open, regardless of the positions of the other switches, andconsequently the motor-circuit cannot be closed unless switches 2 to 5,inclusive, are open and all the resistance R is in circuit with themotor-armature. Now, if switches 2 to 5 are open switch S is depressedand switch 1 is closed. The motor circuit will be closed from lead B,through switch 1, through resistance R and armature A, and also throughfield F in parallel to the resistance, and the armature, to lead B. Themotor consequently starts with all the resistance in series. -Theclosing of switch 1 has shifted contact 7 fromcontact 8 to contact 10,so thatnow switch 2 may be closed without breaking the circuit of magnetM. If, however, any other switch- -such, for instance, as 3 ori,isclosed-instead of closing switch 2 the circuit of magnet M is brokenat contact 16 or contact 20 and switch 1 immediately tripped to open themotor-circuit. After'switch 2 is closed, however, switch 3 may be closedwithout deenergizing the magnet M; but if instead. of closing switch 3either switch a or switch 5 is closed the circuit of magnet M will bebroken. at contact 20 or contact 2 1. )losing switch 3 renders itpossible to close switch 4 without denergizing magnet M, and similarlythe closing of switch t renders it possible to close switch 5withoutbreaking the magnet-circuit. Until switch 5 is closed switch S must beheld depressed, as otherwise the magnet-circuit would be opened andswitch 1 tripped. When switch 5 is closed, however, contact23 bridgescontacts 25. and 26, there'- by short-circuiting switch S and rendcrin'it inoperative. The -urpose of switch S is to make it impossib e for theattendant to close a portion of the switches and then go away, leavingthem in. this condition, which would be exceedingly undesirable,

as the motor-starting resistance is not usually designed. withsufiicient size and heatradiating capacity to carry the motor currentcontinuously. By using switch S it is necessary to close all theswitches be fore leaving them, for otherwise switch 1 would be trippedas soon as switch. S was released by the operator. The use oi switch S,while possessing the advantages above pointed out, is not a necessaryelement of my invention in its broader aspect and may be omitted, inwhich case contacts 27 and 28 would be connected permanently togetherand contact 26 omitted. After the motor has once been started it can beshut down by opening either of switches 2, 3, or 4, there bydeenergizing magnet M, or by tripping the latch L by hand. in eithercase the switch 1 would be thrown open, so as to brealr. themotor-circuit. Then before the motoncir cuit can again be closed it willbe necessary to open. all the other switches, as has been heretoforepointed out. v

Fig. 2 shows switch 1 on an enlarged scale in order to show clearly theoperation of the latch L. The switch may be of any wellknown type, andin practice any standard circuit-breaker construction may. be employed.For the sake of simplicity I have indicated switch 1 as consisting of apivoted lever carrying the laminated contacts U,

adaptedto bridge the stationary contacts when the-'su'ritch is closedand provided with a spring Gt'o throw the switch to open position when"released b the latch. Contact 7 is s aped that when released by rtlleimagnet, so that it moves to 'thBjPDSIiDIOD. indicated in dottedlines, it will prevent the closing of the switch it openor will releaseit if closed. When magnet M is energized, so as to hold I: latch Lin-theposition shown in full lines; the

switch may be closed and when closed'is latched firmlyin position.Thespecific concover all modifications which are withingthe s'co I v atI-claim as new, and desireto secure struction of the switch and latchform'no esired. *I do not desire to limit myself to-the particular;construction and arrangementv of gart of my invention, but may bemodified as.

parts orthespecifio circuit connections here shown, but aim in theappended claims to e of my invention.

byL'etters Patent of the United States, iS- 1.". In combination with ,anelectric cirgc'uit, a pluralit '.ofindependently-Inovable swi'tchesfinsai circuit, and means for auto-..

' matically-breakingsaid circuit upon the closin ofsaidswitches out ofa'predetermined O1 61;

2. In' combination with an' electric CIIF cuit, a plurality ofindependently-movable switches in said circuit, and neans jointlycontrolledby said switches arranged to remain inoperative'upon theclosing of saidswitches serially in a predetermined order and to breaksaid-circuit automatically u, on

, the closing of said switchesout ofsaid or er.

' a plurality of mechanically-independ'ent 3. In combination with anelectric circuit,.a plurality of independently-movable switches in' saidcircuit,- an electromagnet 4s jointly controlled by said switches, and

means'controlled by saidelectromagnet for automatically breakingsaidcircuit upon the closing of said switches outof a predeterminedorder. I

- 4. .In combination with an electric circuit, a plurality ofmechanicall -inde endent switches in said circuit, and e ectricaly-controlled means forpreventing the closing of a' certain one of'saidswitches unless all-the other switches'are open.

In combination with-an electric'circuit,

switches in said circuit, an electromagnet jointly'controlled bycontrolled by said e ectromagnet for preventin the closing of a certainone of said switches un less-all the other switches are open.

6. In combination with an electric circuit,

a plurality of mechanically -independent said switches, and meansswitches in'said circuit,a movable stop adapted in, one positiontoprevent the closingiof a certain one of said switches, a magnet forshifting said step, and a pluralit of switchcontacts contro ed by theseverai switches in circuit withsaid magnet.

7.'.'In combination with an electric--circuit, a pluralityofmechanieally-ihdependent switches in said circuit, a movable stopadapted in one position to prevent the clos ing of a certain one of saidswitches, a magnet adapted when energized to shift said stop to permitthe closing of said switch, and switch-contacts controlled by' theseveral 'switchesarran ed to closethe circuit of said magnet when al ofsaid switches are open. 8. In combination with ah electric circuit, aplurality of independently-movable v switches in said circuit, meansforfpre'venting the closing of acert'ain one of said switches unless allthe other switches'are. open, and means for breaking said'circuit uponthe closing of the remaining switches out of a predetel-mined order;

,cuit, va plurality of. independently -movable switches in said circuit,means for preventing the "closing of acertain one of said switchesunless all the other switches are open, and means for, opening saidswitch upon the clos ing of the. remaining switches out of apredetermined order.

10. In combination, a plurality oi mechannet contro ed jointly by allofsaid switches, and me ans controlled by said magnet for vpreventingthe closing of a certain one of said switches unless -all the otherswitches are '0 en and for opening said switch upon the c osing of theother switches out of a prede ltermined. order. I p

1 1. In combination, a lurality of mechanically-independent switc es,and a tripping device for one vof said switches controlled jointly byauxiliary contacts operatively connected to the several switches.

12. In combinatioma lurality of mechanically-independent swit es,-, aspring tending to open one of said switches, a latch for holding said.switch closed, and anelectromagnet by all of said switches.

13. In combination a pllurality of mechanically-ind'ependent switcdevice for one of said. switches electrlcally controlled by all of saidswitchesjointlyr 14. In combinatioma luralit of mechantricallycontrolledby ail-of said switches .jointl for preventing'the closing of a certainone-o said switches: Y

. 15. In combination, a lurality of mechanically independe'nt' switc esand means eiectrically controlled by all of said switches controllingsaidilatch and i'ointly controlled ically-independent switc es an meanselec.-

49. In combination .with. an el'ectric..-cir

ic'ally-inde endent switches, an electromag es and a tripping seajointly for preventing the closing of a certain one of said switches,and for tripping said switch when closed.

16. In combination with an electric circuit, a lurality of switches insaid circuit, a' novoltage release device operatively connected. to oneof said switches, and contacts controlled by'the other switchescontrollingsaid device.

17. In combination with anelectric circuit, a plurality of switches insaid circuit, a novoltage'release device operatively connected to one ofsaid switches, and. means for deenergizing said device upon the'closingof the other switches out of a redetermined order.

18. In combination with an electric circuit, a plurality of switches insaid circuit, a novoltage release device operatively connected to one ofsaid switches, and switch-contacts controlled by the other switchesarranged to break the circuit of said device upon the closing of saidswitches. out of a predetermined order.

ll). In combination with an electric circuit, a switch in said circuit,and a no-voltage re lease device arranged when deenergized to rnevcntthe closing of said switch.

20. In combination, a switch, a magnet, and means controlled by saidmagnet for preventing the closing of said switch and trip ping saidswitch when closed when said magnet is dcenergized.

21. In combination with an electric circuit, a switch arranged to closesaid circuit, a magnet connected in shunt to said circuit, and

means controlled by said magnet for prevent-' ing the closing of saidswitch and tripping said switch when-closed when said magnet isdecnergized.

22. In combination with an electric circuit, a plurality of mechanicallyindependent switches in said circuit, a no-voltage release deviceoperatively connected to one of said switches and arranged whende'energized to prevent the closing of said switch, and contactscontrolled by the other switches controlling said device.

23. In combination with a rheostat, a plurality ofmechanically-independent switches controlling the resistance thereof,and means for'automatically breaking the circuit of said rheostat uponthe closing ofsaid switches out of a predetermined order.

24. In combination with arheostat, a plurality ofmechanically-independent switches controlling theresistance thereof, anelectro magnet jointly controlled by said switches, and means controlledby said-magnet for automatically breaking the circuit of said rheostat.

25. In combination with a rheostat, aplurality ofmechanicallyindependentswitches controlling the resistance thereof, ano-volta .e release device, and contacts controlled by said switches andcontrolling said device.

26. Iii-combination with a-rheostat, a'plurality ofmechanically-independent switchescontrolling the resistance thereof,a=no-voltage release device, and contacts controlled by said switchesand arranged to break the Oil cuit of said device upon-the closingiofsaid switches out of a'predeterniinedorder.

27-. In combination witlr a rheostat', aswitch arranged to close thecircuit ofthe rheostat, a-plurality of meohanically-independent switchesarran ed-to short-circuit different sections of saidrheostat,and-means-for automatically opening the first-named switch upon theclosing of the other switches out ofa predeterminedorden' In combinationwith arheostat, a switch arranged to close the circuit of the rheostat,a plurality of mechanically-inde-- pendent switches arranged toshort-circuit different sections of said rheostat,-andelectrically-controlled means-forpreventing the closing of the first-namedswitch unless the other switches are open.

29. In combination with a rheostat, a-- switch arranged to close thecircuit of the rheostat, a plurality of 1nechanically-independentswitches arranged to short-circuit different sections of said rheostat,electricallycontrolled means for preventing the closing, of thefirst-named switch unless the other switches are open, and means forautomatically opening the first-named'switch upon-the closing of theother switches out of a prede termined order.

30. In combination with a rheostat, a switch arranged to'openthe circuitof said rheostat, a trip device controlling said switch, a plurality ofmechanically-independent switches arranged to short-circuit differentsections of said rheostat, and contacts controlled by sai'dswitchesandcontrollingsaid trip device.

3 1. In combination with a rheostat, a in anually-operatedswitcharrangedto open the circuit of said rheostat, an electromagnetccntrolling the opening-and closing of said switch, a plurality ofmechanically independent switches arranged tocut out difierentsectionsof said rheostat, and contacts controlled by said switches andcontrolling said electromagnet. V

32. In combination with an electric circuit, a plurality ofindependently-movable switches in said circuit, an electromagnet, me anscontrolled by said magnet forbreaking said circuit when the magnet isdeenergized,

contacts controlled by said switches for -deenergizing said magnetupon-the closing of said switches out of a'predetermined order, and-anormally open-switch in circuit with saidmagnet and arranged to beshort-cincuited by the closing of the last of the firstnamed switches. A

33. In combination with an-electriccir-- cuit, a plurality ofindependently-movable 1 c switches in said circuit, an electromagnet,means controlled by said magnet for breaking said circuit when themagnet is dener- %ized, contacts controlled by said switches ordeenergizing said magnet upon the closing "of said switches out of apredetermined order,

and a switch arranged normally to denergize said magnet and to berendered inoperative by the closing of the last of the first-namedswitches.

34. In combination with an electric circuit, a plurality ofindependently-movable switchesin said circuit, an electromagnet,

means controlled by said electromagnet-for breaking said circuit,contacts controlled by 5 said switches and jointly controlling saidelectromagnet, and a spring-actuated switchcontrolling saidelectromagnet and arranged to be rendered inoperative by the closing ofthe last of the first-mentioned switches.

In Witness whereof I have hereunto set my hand thisSlst day of January,1906.

' LAURENCE A. HAWKINS.

Witnesses:

BENJAMIN B. HULL,

HELEN ORFORD.

